Mycosis fungoides (MF)
does not develop from other dermatoses. Names like parapsoriasis
en plaque, parapsoriasis variegata and poikiloderma atrophicans
vasculare are simply descriptive terms of large patch lesions of
MF. Such antiquated and confusing terms are better abandoned.

Classification
of ‘premycotic’ eruptions
(terms in italics are
the recommended new nomenclature):

Parapsoriasis
en plaque: not all types are ‘premycotic’

Prereticulotic
(large plaque type): when the histology is not (yet)
confirmatory, the condition can be designated ?MF
stage T0 or premycosis.

Poikiloderma
atrophicans vasculare (PAV): not all types are
premycotic

MF-associated,
prereticulotic poikiloderma (parapsoriasis variegata):
the histological picture is usually diagnostic of MF (more
pronounced infiltrate than in ordinary non-MF-associated
poikiloderma, MF or Lutzner cells may be seen as well as
epidermotropism); the condition can be
designated poikilodermatous MF—MF T1 or stage
IA.